Preparing for your National Car Test (NCT) can be stressful, particularly if you rely on your car every day and cannot afford unexpected repair costs or delays.
The good news is that some common reasons for NCT failure can be identified before you arrive at the test centre. Checking your tyres, lights, brakes and other important components can help you spot potential problems early and arrange repairs where necessary.
However, an NCT is more than a quick visual inspection. It assesses several aspects of your vehicle’s roadworthiness, and passing a few basic checks does not guarantee a successful result.
If your NCT is approaching, here are seven areas worth checking before your appointment.
1. Tyres: Tread Depth, Damage and Condition
Tyres are one of the most important things to check before an NCT. According to an RSA announcement published in October 2026, tyre condition remained the leading cause of NCT failures, with 193,232 motorists failing for this reason over the preceding 12 months.
The legal minimum tread depth for ordinary car tyres in Ireland is 1.6mm. However, tyres can also fail inspection because of damage, unsuitable specifications or other defects.
Before your test, check for:
- Tread worn down towards or below the legal minimum.
- Cuts, bulges or other visible damage to the tyre.
- Uneven wear across the tread.
- Incorrect tyre pressure.
- Tyres that appear unsuitable or incorrectly fitted.
Uneven wear can sometimes indicate a problem with wheel alignment, suspension or another component. If you notice unusual wear, ask a garage to inspect the cause rather than simply replacing the tyre.
You should also check that the tyres are inflated to the manufacturer’s recommended pressure.
What to do: If a tyre has significant damage, insufficient tread or another concerning defect, arrange a professional assessment before the test. Do not wait until the NCT to address a potentially unsafe tyre.
2. Brakes and Brake Lines
Your vehicle’s braking system is essential for road safety and is an important part of the NCT.
The inspection can identify problems with braking performance, brake components, pipes, flexible hoses and other parts of the system.
Potential issues include:
- Worn brake pads or discs.
- Damaged or corroded brake pipes.
- Deteriorated or damaged flexible brake hoses.
- Brake fluid leaks.
- A parking brake that does not operate effectively.
- Warning lights indicating a braking-system fault.
Some brake problems are difficult to identify without specialist equipment or an inspection underneath the vehicle.
Pay attention to symptoms such as unusual noises when braking, vibration through the pedal, a vehicle pulling to one side or a handbrake that does not hold the car properly.
These symptoms do not all indicate the same fault, so a proper inspection is important.
What to do: If you notice a change in braking performance or suspect a brake fault, arrange an inspection promptly. If the brakes may be unsafe, do not drive the vehicle to the garage; ask about recovery.
3. Lights and Headlamp Aim
A light that works but points in the wrong direction can still cause problems during the NCT.
The test checks various lighting components, including headlights, indicators, brake lights, position lamps and registration plate lights. Their condition, operation, colour and alignment may all be relevant.
Before your appointment, check that:
- Both headlights operate correctly.
- Headlights are securely fitted and correctly aligned.
- Indicators work and are clearly visible.
- Brake lights illuminate when the brake pedal is pressed.
- Registration plate lights work.
- Lenses are not broken or missing.
- There is no obvious damage or moisture affecting a light unit.
Ask someone to help you check the rear lights while you operate the controls. If you are alone, you may be able to use a reflection or safely positioned phone camera to confirm that the lights illuminate.
Headlamp aim deserves particular attention. The NCTS has highlighted it as a significant cause of failure, and replacing a bulb can sometimes affect its alignment.
What to do: If a light is faulty or the beam appears incorrectly positioned, have it checked before your test. A garage can assess the lighting system and adjust the headlamp aim where necessary.
4. Suspension and Steering
Suspension and steering components affect how your vehicle handles, maintains contact with the road and responds to driver input.
Wear or damage may not always be obvious during a quick walk-around, but certain symptoms can indicate that an inspection is needed.
Look out for:
- Knocking noises when travelling over bumps.
- Excessive bouncing after driving over an uneven surface.
- Uneven tyre wear.
- Unusual movement or looseness in the steering.
- The vehicle pulling to one side.
- Visible damage to accessible suspension components.
These symptoms can have several causes. For example, uneven tyre wear might relate to alignment, suspension wear or tyre pressure rather than one specific defective component.
A proper inspection can help identify the underlying problem.
What to do: If you notice unusual steering behaviour, persistent knocking or excessive bouncing, arrange a professional inspection before the NCT. Do not assume the vehicle will pass simply because it still feels driveable.
5. Seat Belts and Safety Restraints
Seat belts are essential safety equipment and are checked during the NCT.
A belt that is damaged, badly frayed, incorrectly repaired or not operating properly can cause a failure.
Before the test, check that:
- Seat belts extend and retract normally.
- Buckles fasten securely and release correctly.
- Belts are not cut, badly frayed or visibly damaged.
- Buckles and mounting points show no obvious damage.
- The belts are accessible and not obstructed by personal belongings.
Do not attempt to repair a damaged seat belt with adhesive, stitching or makeshift materials. Safety restraints must remain suitable for their intended purpose.
If a belt does not lock or retract correctly, or if the buckle will not secure properly, have it inspected.
What to do: Arrange the necessary repair before your test if a seat belt or its fastening mechanism is defective.
6. Exhaust System and Emissions
An exhaust or emissions problem can also affect your NCT result.
The inspection may identify exhaust leaks, damaged components, excessive noise or emissions outside the applicable limits. The precise checks depend on the vehicle and the relevant testing requirements.
Potential warning signs include:
- Unusual exhaust noise.
- Visible damage or corrosion to the exhaust system.
- Exhaust fumes entering the passenger compartment.
- An engine warning light.
- Poor engine running or unusual smoke.
Emissions-related problems can have several causes, including engine-management faults, sensor issues or problems with emissions-control equipment.
A warning light does not automatically identify which part needs replacing. Diagnostic testing may be needed to establish the underlying cause.
What to do: If you suspect an exhaust or emissions fault, arrange an inspection before the test. Avoid replacing components based only on guesswork, as the actual cause may be elsewhere in the system.
7. Windscreen Wipers, Washers and Driver Visibility
Your windscreen must provide the driver with an adequate view of the road, and the wipers and washers play an important role in maintaining visibility.
These items are particularly worth checking in Ireland, where rain and road spray can make clear visibility essential.
Before your NCT, check that:
- Wiper blades clear the windscreen effectively.
- Blades are not badly damaged or worn.
- The washer system operates correctly.
- There is sufficient washer fluid.
- Washer jets direct fluid onto the appropriate area of the windscreen.
- The windscreen does not have damage that could affect visibility or fail the applicable inspection requirements.
Wiper blades are relatively straightforward to inspect, but windscreen damage may require a professional assessment to determine whether it meets the NCT requirements.
What to do: Replace ineffective wiper blades, refill washer fluid and address faults in the washer system before your appointment. If the windscreen is damaged, check whether it needs repair or replacement.
Other Checks to Complete Before Your NCT
The seven areas above are useful starting points, but they are not a complete list of everything inspected during an NCT.
You should also check your registration plates, horn, mirrors, general vehicle condition and other relevant items.
The official NCTS pre-NCT checklist provides additional guidance on preparing your vehicle for the test.
It is also worth making sure that the vehicle is reasonably clean, the boot is cleared of unnecessary belongings, seat belts are accessible and any removable items that could obstruct the inspection have been taken out.
If your vehicle has an illuminated warning light, an unusual noise or a known mechanical issue, do not ignore it simply because it is not listed in this article.
Should You Book a Pre-NCT Inspection?
A pre-NCT inspection can help identify potential problems before your scheduled test.
A garage may be able to examine tyres, brakes, suspension, lights, steering and other relevant components, depending on the inspection package you choose.
It is important to understand what is included. A basic visual inspection is not necessarily the same as a comprehensive mechanical inspection, and neither guarantees that the vehicle will pass the NCT.
If the garage identifies a defect, ask it to explain:
- What the problem is.
- Why the repair is recommended.
- Whether it affects road safety.
- What the repair will involve.
- How much the work is expected to cost.
- Whether additional testing or repairs may be required.
Request a written quote and confirm that additional chargeable work will not proceed without your approval.
If a defect could make the car unsafe to drive, follow the garage’s safety advice and arrange appropriate recovery if necessary.
What Happens If Your Car Fails the NCT?
If your vehicle fails, you will receive a Vehicle Inspection Report (VIR) identifying the defects recorded during the test.
Read the report carefully and use it to understand which items need attention. If anything is unclear, ask the test centre or a suitable garage to explain the findings.
Arrange the required repairs and follow the NCTS instructions for booking your re-test. Re-test arrangements and deadlines depend on the applicable rules and the nature of the inspection, so check the current official guidance rather than assuming every failure follows the same process.
A dangerous result is especially serious. A vehicle with a dangerous defect must not be driven on public roads until the defect has been rectified and the required testing requirements have been met.
If you are unsure whether your vehicle is safe to drive, seek professional advice and arrange recovery where appropriate.
Prepare Your Car Before Test Day
A few checks before your NCT can help you identify issues early, reduce avoidable delays and make informed decisions about repairs.
Start with your tyres, brakes, lights, suspension, seat belts, exhaust and windscreen wipers. If you find a problem, arrange a suitable inspection instead of assuming it will pass.
Remember that the NCT assesses roadworthiness at the time of testing. Regular servicing and maintenance remain important throughout the year, not just in the weeks before your test.
RepairMyCar.ie helps drivers across Ireland connect with vetted independent garages for NCT-related repairs, servicing, diagnostics and other car maintenance. You can explain the issue, request a written quote and review the proposed work before deciding how to proceed.
Getting ready for your NCT? Request a quote through RepairMyCar.ie to discuss the checks or repairs your vehicle may need before its test.
